| 1. |
- Henein, Michael Y., et al.
(författare)
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Biomarkers predict in-hospital major adverse cardiac events in covid-19 patients : A multicenter international study
- 2021
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Ingår i: Journal of Clinical Medicine. - : MDPI. - 2077-0383. ; 10:24
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Tidskriftsartikel (refereegranskat)abstract
- Background: The COVID-19 pandemic carries a high burden of morbidity and mortality worldwide. We aimed to identify possible predictors of in-hospital major cardiovascular (CV) events in COVID-19.Methods: We retrospectively included patients hospitalized for COVID-19 from 10 centers. Clinical, biochemical, electrocardiographic, and imaging data at admission and medications were collected. Primary endpoint was a composite of in-hospital CV death, acute heart failure (AHF), acute myocarditis, arrhythmias, acute coronary syndromes (ACS), cardiocirculatory arrest, and pulmonary embolism (PE).Results: Of the 748 patients included, 141(19%) reached the set endpoint: 49 (7%) CV death, 15 (2%) acute myocarditis, 32 (4%) sustained-supraventricular or ventricular arrhythmias, 14 (2%) cardiocirculatory arrest, 8 (1%) ACS, 41 (5%) AHF, and 39 (5%) PE. Patients with CV events had higher age, body temperature, creatinine, high-sensitivity troponin, white blood cells, and platelet counts at admission and were more likely to have systemic hypertension, renal failure (creatinine ≥ 1.25 mg/dL), chronic obstructive pulmonary disease, atrial fibrillation, and cardiomyopathy. On univariate and multivariate analysis, troponin and renal failure were associated with the composite endpoint. Kaplan–Meier analysis showed a clear divergence of in-hospital composite event-free survival stratified according to median troponin value and the presence of renal failure (Log rank p < 0.001).Conclusions: Our findings, derived from a multicenter data collection study, suggest the routine use of biomarkers, such as cardiac troponin and serum creatinine, for in-hospital prediction of CV events in patients with COVID-19.
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| 2. |
- Beck, Lisa J., et al.
(författare)
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Differing Mechanisms of New Particle Formation at Two Arctic Sites
- 2021
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 48:4
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Tidskriftsartikel (refereegranskat)abstract
- New particle formation in the Arctic atmosphere is an important source of aerosol particles. Understanding the processes of Arctic secondary aerosol formation is crucial due to their significant impact on cloud properties and therefore Arctic amplification. We observed the molecular formation of new particles from low-volatility vapors at two Arctic sites with differing surroundings. In Svalbard, sulfuric acid (SA) and methane sulfonic acid (MSA) contribute to the formation of secondary aerosol and to some extent to cloud condensation nuclei (CCN). This occurs via ion-induced nucleation of SA and NH3 and subsequent growth by mainly SA and MSA condensation during springtime and highly oxygenated organic molecules during summertime. By contrast, in an ice-covered region around Villum, we observed new particle formation driven by iodic acid but its concentration was insufficient to grow nucleated particles to CCN sizes. Our results provide new insight about sources and precursors of Arctic secondary aerosol particles.
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| 3. |
- Cooil, Simon P., et al.
(författare)
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In Situ Patterning of Ultrasharp Dopant Profiles in Silicon
- 2017
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 11:2, s. 1683-1688
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Tidskriftsartikel (refereegranskat)abstract
- We develop a method for patterning a buried two-dimensional electron gas (2DEG) in silicon using low kinetic energy electron stimulated desorption (LEESD) of a monohydride resist mask. A buried 2DEG forms as a result of placing a dense and narrow profile of phosphorus dopants beneath the silicon surface; a so-called δ -layer. Such 2D dopant profiles have previously been studied theoretically, and by angle-resolved photoemission spectroscopy, and have been shown to host a 2DEG with properties desirable for atomic-scale devices and quantum computation applications. Here we outline a patterning method based on low kinetic energy electron beam lithography, combined with in situ characterization, and demonstrate the formation of patterned features with dopant concentrations sufficient to create localized 2DEG states.
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| 4. |
- Giani, Alessandro, et al.
(författare)
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Benchmarking of minimally invasive distal pancreatectomy with splenectomy: European multicentre study
- 2022
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Ingår i: British Journal of Surgery. - : OXFORD UNIV PRESS. - 0007-1323 .- 1365-2168. ; 109:11, s. 1124-1130
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to assess best achievable outcomes in minimally invasive distal pancreatectomy with splenectomy, applying the Achievable Benchmark of Care method. This method of assessing outcomes should positively encourage comparisons, allowing single surgeons or entire units to anonymously and individually recognize what works well and where there might be room for improvement. Background Benchmarking is the process to used assess the best achievable results and compare outcomes with that standard. This study aimed to assess best achievable outcomes in minimally invasive distal pancreatectomy with splenectomy (MIDPS). Methods This retrospective study included consecutive patients undergoing MIDPS for any indication, between 2003 and 2019, in 31 European centres. Benchmarks of the main clinical outcomes were calculated according to the Achievable Benchmark of Care (ABC (TM)) method. After identifying independent risk factors for severe morbidity and conversion, risk-adjusted ABCs were calculated for each subgroup of patients at risk. Results A total of 1595 patients were included. The ABC was 2.5 per cent for conversion and 8.4 per cent for severe morbidity. ABC values were 160 min for duration of operation time, 8.3 per cent for POPF, 1.8 per cent for reoperation, and 0 per cent for mortality. Multivariable analysis showed that conversion was associated with male sex (OR 1.48), BMI exceeding 30 kg/m(2) (OR 2.42), multivisceral resection (OR 3.04), and laparoscopy (OR 2.24). Increased risk of severe morbidity was associated with ASA fitness grade above II (OR 1.60), multivisceral resection (OR 1.88), and robotic approach (OR 1.87). Conclusion The benchmark values obtained using the ABC method represent optimal outcomes from best achievable care, including low complication rates and zero mortality. These benchmarks should be used to set standards to improve patient outcomes.
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| 5. |
- Krieger, Jonas A., et al.
(författare)
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Weyl spin-momentum locking in a chiral topological semimetal
- 2024
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Ingår i: Nature Communications. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Spin-orbit coupling in noncentrosymmetric crystals leads to spin-momentum locking – a directional relationship between an electron’s spin angular momentum and its linear momentum. Isotropic orthogonal Rashba spin-momentum locking has been studied for decades, while its counterpart, isotropic parallel Weyl spin-momentum locking has remained elusive in experiments. Theory predicts that Weyl spin-momentum locking can only be realized in structurally chiral cubic crystals in the vicinity of Kramers-Weyl or multifold fermions. Here, we use spin- and angle-resolved photoemission spectroscopy to evidence Weyl spin-momentum locking of multifold fermions in the chiral topological semimetal PtGa. We find that the electron spin of the Fermi arc surface states is orthogonal to their Fermi surface contour for momenta close to the projection of the bulk multifold fermion at the Γ point, which is consistent with Weyl spin-momentum locking of the latter. The direct measurement of the bulk spin texture of the multifold fermion at the R point also displays Weyl spin-momentum locking. The discovery of Weyl spin-momentum locking may lead to energy-efficient memory devices and Josephson diodes based on chiral topological semimetals.
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| 6. |
- Marković, Igor, et al.
(författare)
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Electronically driven spin-reorientation transition of the correlated polar metal Ca3Ru2O7
- 2020
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 117:27, s. 15524-15529
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Tidskriftsartikel (refereegranskat)abstract
- The interplay between spin-orbit coupling and structural inversion symmetry breaking in solids has generated much interest due to the nontrivial spin and magnetic textures which can result. Such studies are typically focused on systems where large atomic number elements lead to strong spin-orbit coupling, in turn rendering electronic correlations weak. In contrast, here we investigate the temperature-dependent electronic structure of Ca3Ru2O7, a 4d oxide metal for which both correlations and spin-orbit coupling are pronounced and in which octahedral tilts and rotations combine to mediate both global and local inversion symmetry-breaking polar distortions. Our angle-resolved photoemission measurements reveal the destruction of a large hole-like Fermi surface upon cooling through a coupled structural and spinreorientation transition at 48 K, accompanied by a sudden onset of quasiparticle coherence. We demonstrate how these result from band hybridization mediated by a hidden Rashba-type spin- orbit coupling. This is enabled by the bulk structural distortions and unlocked when the spin reorients perpendicular to the local symmetry-breaking potential at the Ru sites. We argue that the electronic energy gain associated with the band hybridization is actually the key driver for the phase transition, reflecting a delicate interplay between spin-orbit coupling and strong electronic correlations and revealing a route to control magnetic ordering in solids.
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| 7. |
- Mazzola, Federico, et al.
(författare)
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Disentangling phonon and impurity interactions in delta-doped Si(001)
- 2014
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 104:17
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Tidskriftsartikel (refereegranskat)abstract
- We present a study of the phonon and impurity interactions in a shallow two dimensional electron gas formed in Si(001). A highly conductive ultra-narrow n-type dopant delta-layer, which serves as a platform for quantum computation architecture, is formed and studied by angle resolved photoemission spectroscopy (ARPES) and temperature dependent nanoscale 4-point probe (4PP). The bandstructure of the delta-layer state is both measured and simulated. At 100 K, good agreement is only achieved by including interactions; electron-impurity scattering (W-0 = 56 to 61 meV); and electron-phonon coupling (lambda = 0.14 +/- 0.04). These results are shown to be consistent with temperature dependent 4PP resistance measurements which indicate that at 100 K, approximate to 7/8 of the measured resistance is due to impurity scattering with the remaining 1/8 coming from phonon interactions. In both resistance and bandstructure measurements, the impurity contribution exhibits a variability of approximate to 9% for nominally identical samples. The combination of ARPES and 4PP affords a thorough insight into the relevant contributions to electrical resistance in reduced dimensionality electronic platforms. (C) 2014 AIP Publishing LLC.
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| 8. |
- Mazzola, Federico, et al.
(författare)
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Kinks in the σ Band of Graphene Induced by Electron-Phonon Coupling
- 2013
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 111:21, s. 216806-
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Tidskriftsartikel (refereegranskat)abstract
- Angle-resolved photoemission spectroscopy reveals pronounced kinks in the dispersion of the σ band of graphene. Such kinks are usually caused by the combination of a strong electron-boson interaction and the cutoff in the Fermi-Dirac distribution. They are therefore not expected for the σ band of graphene that has a binding energy of more than ≈3.5 eV. We argue that the observed kinks are indeed caused by the electron-phonon interaction, but the role of the Fermi-Dirac distribution cutoff is assumed by a cutoff in the density of σ states. The existence of the effect suggests a very weak coupling of holes in the σ band not only to the π electrons of graphene but also to the substrate electronic states. This is confirmed by the presence of such kinks for graphene on several different substrates that all show a strong coupling constant of λ≈1.
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| 9. |
- Mazzola, Federico, et al.
(författare)
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Strong electron-phonon coupling in the sigma band of graphene
- 2016
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Ingår i: arXiv. ; , s. 1-11
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- First-principles studies of the electron-phonon coupling in graphene predict a high coupling strength for the ? band with values of the dimensionless electron-phonon coupling constant ? up to 0.9. Near the top of the ? band ? is found to be ≈ 0.7. This value is consistent with the observed kink in the ? band dispersion near the Γ-point in the Brillouin zone [1]. The calculations show that the electron-phonon coupling is driven primarily by the optical LO and TO phonon modes in graphene. The photoemission intensity from the ? band is strongly suppressed near the Γ-point due to sub-lattice interference effects. These effects are removed by taking data in the neighbouring Brillouin zone. By this we have been able to disentangle the influence of sub-lattice interference and electron-phonon coupling. Whilst superconductivity has been absent from graphene's list of exceptional properties, despite considerable experimental attempts, we speculate that if the strong EPC in the ? band survives a modification that shifts it to the Fermi level, e.g. by means of atomic substitution, a superconducting transition temperatures of around 70 K could be reached.
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| 10. |
- Mazzola, Federico, et al.
(författare)
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The sub-band structure of atomically sharp dopant profiles in silicon
- 2020
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Ingår i: npj Quantum Materials. - : Springer Science and Business Media LLC. - 2397-4648. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- The downscaling of silicon-based structures and proto-devices has now reached the single-atom scale, representing an important milestone for the development of a silicon-based quantum computer. One especially notable platform for atomic-scale device fabrication is the so-called Si:P δ-layer, consisting of an ultra-dense and sharp layer of dopants within a semiconductor host. Whilst several alternatives exist, it is on the Si:P platform that many quantum proto-devices have been successfully demonstrated. Motivated by this, both calculations and experiments have been dedicated to understanding the electronic structure of the Si:P δ-layer platform. In this work, we use high-resolution angle-resolved photoemission spectroscopy to reveal the structure of the electronic states which exist because of the high dopant density of the Si:P δ-layer. In contrast to published theoretical work, we resolve three distinct bands, the most occupied of which shows a large anisotropy and significant deviation from simple parabolic behaviour. We investigate the possible origins of this fine structure, and conclude that it is primarily a consequence of the dielectric constant being large (ca. double that of bulk Si). Incorporating this factor into tight-binding calculations leads to a major revision of band structure; specifically, the existence of a third band, the separation of the bands, and the departure from purely parabolic behaviour. This new understanding of the band structure has important implications for quantum proto-devices which are built on the Si:P δ-layer platform.
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